Image: Third rail at South Station, October 2002
Description: Third rail at the South Station stop on the MBTA Red Line. While the third rail shown here may look old and grungy, it is actually advanced mass transit technology. Third rail is subject to heavy wear and must be made out a strong material, typically steel. Unfortunately, steel is a relatively poor electrical conductor. A new method for reducing the resulting resistive losses is to attach strips of aluminum (which is a better conductor of electricity) to the steel third rail. Since aluminum has a different coefficient of thermal expansion from steel, the strips must be applied on both sides and riveted at frequent intervals. The third rail pictured here uses this method.
Title: Third rail at South Station, October 2002
Credit: Own work
Author: Original file by ArnoldReinhold at English Wikipedia A later version was uploaded by Deltabeignet at English Wikipedia
Usage Terms: Creative Commons Attribution-Share Alike 3.0 truetrue
License: CC-BY-SA-3.0
License Link: http://creativecommons.org/licenses/by-sa/3.0/
Attribution Required?: Yes
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